The invention provides an improved waterproofing system for the concrete slab of a flat roof on a building. More specifically, the invention relates to a construction method for installing a waterproofing layer by using a plastic panel of designed size on the concrete substrate, and installing a supplementary waterproofing layer by using a general sheet membrane material such as asphalt sheet, metal sheet and other sheets on a vertical surface, especially parapet, and further relates to a multi-ply construction method for installing fluid-applied materials and reinforcing fiber meshes on the surface to connect the plastic panel layer on substrate with the sheet membrane layer on the vertical surface.
In the conventional waterproofing systems for the concrete substrate, especially roofs on buildings, a single-ply waterproofing system by using fluid-applied materials such as urethane or polymeric asphalt and cementitious materials, or sheet membrane materials such as thermoplastics, rubberized asphalt, vulcanized rubberized and stainless steel is well known.
However, the single-ply waterproofing system by using fluid-applied materials is apt to be affected by the surface condition of the substrate, weather, and condition of the roof that may create blisters, debondment, tears, cracks, etc. It is also difficult to prevent water leakage at the overlapped joint of a sheet membrane. Thus, labor expenses and time increase to prepare the substrate and to repair defects of the waterproofing layer.
In order to solve the problems of single-ply waterproofing systems that use fluid-applied materials or sheet membrane, a proposal has been made to install a multi-ply or double-ply membrane which uses both fluid-applied materials and sheet membranes as a multi-ply waterproofing system of urethane and modified asphalt sheet, or a multi-ply waterproofing system of cementitious materials and stainless steel plate.
Although the proposed waterproofing system has solved some problems of the single-ply waterproofing system, other problems still remain unsolved as follows:
First, in case of the multi-ply waterproofing system of urethane and modified asphalt sheet, because both materials are flexible, it is difficult to make a sloped waterproofing layer adaptable for fast water drainage. Accordingly, there are many places where rain or melted snow stagnates on the waterproofing layer, which ultimately causes the waterproofing layer to become aged, faded, cracked and blistered. Because of the flexible property, this system does not withstand the pressure occurring from foot traffic and movement of objects for utility of a roof space.
Second, multi-ply waterproofing systems that use cementitious materials and stainless steel plate have shortcomings such as debondment of the waterproofing layer between the materials and noise occurring when a workman walks on the waterproofing layer. Metal sheet is deformed by thermal expansion and contraction, and the overlapped joint may burst open. Thus, it is hard for a worker to carry and treat the metal sheet. For this reason, construction delays occur and labor and construction costs are increased.
Third, since each material of the multi-ply waterproofing system has a different surface condition and adhesion mechanism, the system cannot gain a good adhesion to adjacent materials after application. The problems of blistering, cracking and tearing caused by weather affect the overlapped part of sheet membranes during many application steps of the multi-ply waterproofing system.
Finally, because installation of the multi-ply waterproofing system is mainly made at the job site, weather may affect many installation steps such as carrying, mixing, application, curing and setting of a ventilation plate, and overlapping and sealing of seams in every material such as fluid-applied materials or sheets. There is a need in the art for a waterproofing method that overcomes these problems with known waterproofing systems.
The present invention provides a multi-ply waterproofing system in which the waterproofing layer uses a hollow plastic panel of designed size, holes and thickness on a concrete slab of a flat roof on a building. The waterproofing system includes a supplementary waterproofing layer that uses general membrane materials such as asphalt sheets, metal sheets and other membrane sheets on the vertical elements, especially the parapet, of the roof.
The single-ply system that uses fluid-applied materials for waterproofing a flat roof on buildings is apt to be affected by the surface condition of the substrate, weather and condition of the roof that may create blisters, debondment, tears, cracks, etc. In case of a single-ply system using sheet membrane, it is difficult to prevent water leakage at an overlapped joint of a sheet membrane. Thus, working hours and expenses increase to prepare the substrate and to repair defects of the waterproofing layer.
The invention provides an improved waterproofing system for the concrete slab of a flat roof on a building. More specifically, the invention relates to the construction method for installing the waterproofing layer by using a hollow plastic panel of designed size and thickness on a concrete substrate, and installing the supplementary waterproofing layer by using sheet membrane materials on the vertical surface, especially the parapet of the roof. The invention further relates to the construction method for installing reinforcing fiber meshes on the joint line that connects the plastic panels on the flat substrate with the sheet membrane layer on the vertical surface. A main property of the invention is to install the waterproofing layer of sloped-step type hollow plastic panels of a different thickness for fast drainage of stagnant water, which otherwise would cause physical damage in the performance of the waterproofing layer. Several important features of the invention are as follows:
1. The plastic panel has several hollow parts in the inside thereof which may be configured in a variety of cross-sectional shapes, such as a circle or square. The upper or lower face of the edge parts in the plastic panel preferably has groove and tongue joints for connecting the panels together. This joint permits the space protection of the panel layer against the thermal expansion and contraction. Other panel connection methods may also be utilized.
2. The plastic panel preferably has holes for fixing the panels on the substrate and for setting the special plates to ventilate the moisture existing in the space between the panels and the substrate.
3. The waterproofing layer on substrate is installed as a sloped step to easily drain the stagnant water on the waterproofing layer. The plastic panels may have a size of about 1 mxc3x971 m (or about one square yard in size), and from 2-15 cm in thickness.
4. The lines of the panels connected by the groove and the tongue joint are reinforced with sheet tape made of high strength of fiber, such as carbon fiber, glass fiber, armada fiber, etc. for preventing water penetration and movement of panels. At this time, the reinforcing tapes are preferably adhesive tapes.